| Surface wettability has a great significance in the fields of human production and life.When the contact angle is close to 0°(superlyophilic)or greater than 150°(superlyophobic),the surface is defined as a superwetting surface.It has been found that superlyophobic surfaces with liquid-repellent functions have a good application potential in the fields of droplet manipulation,friction control,self-cleaning,and oil-water separation.Therefore,superlyophobic surfaces have attracted widespread attention.It is well known that surface wettability is not only affected by chemical compositions,but also depends on microstructures.However,it remains difficult to design microstructured superlyophobic surfaces with good performance to meet the requirements of daily production and life.The conventional design of microstructures is lack of design basis,and it is often difficult to obtain the desired superlyophobic surfaces.After evolution of billions of years,special microstructured arrays have been formed on many organisms.The combination of microstructured arrays and chemical compositions results in the superlyophobicity of organism surface.The self-assembly and self-arrangement of the microstructured arrays on the surfaces of natural organisms provide new ideas for bionic designs.In recent years,many methods have been used to construct microarrayed superlyophobic surfaces,such as coating,templating,laser processing,photolithography,and 3D printing.Despite the advantages of these methods for fabricating excellent superlyophobic surfaces,there are still some limitations that need to be overcome.Thus,questing for a suitable fabrication method and performing bionic design and optimization to construct bionic microarrayed superlyophobic surfaces remain challenges,which are also the frontiers and hot spots of the current researches.Inspired by four typical organisms(lotus,rose,springtail,and Nepenthes)with superlyophobic surfaces,four bionic microarrayed superlyophobic surfaces with different performance and function,including low-adhesion superhydrophobic surface,high-adhesion superhydrophobic surface,superomniphobic surface,and slippery surface were successfully prepared by coating,templating,self-assembly,and self-assembly@dip-coating methods based on the bionic design principles of superlyophobic surfaces,respectively.The internal relationships between the microstructured array and surface wettability were revealed.The applications of bionic surfaces in droplet manipulation,friction control,self-cleaning,and oil-water separation were explored.It is anticipated that this study could provide a theoretical basis and technical support for the controllable manufacturing and large-scale application of bionic superlyophobic surfaces.The main research contents and conclusions are as follows:(1)Inspired by the low-adhesion superhydrophobic surface with micro/nanopapillae of lotus leaf,an environmentally-friendly multifunctional superhydrophobic coating with micro/nano convex hull was designed,and then prepared using the one-step method.The results showed that the coating possessed superhydrophobicity and mechanical stability.Besides,the coated glass slides showed excellent self-cleaning ability in air,oil,and after being polluted by oil.The coated stainless steel meshes demonstrated continuous oil-water separation ability,and the separation efficiency of various oil-water mixtures was higher than 93%.The coated 45# steels showed long-term anti-friction ability.(2)Inspired by the high-adhesion superhydrophobic surface with microscale papillae and nanoscale folds of rose,micropillar arrays with nano convex hull were designed,and then fabricated on the surface of shape memory epoxy resin by the templating method.After modification by a fluorinated silane,a high-adhesion superhydrophobic surface with programmable micro/nano-structures and wettability was obtained.The programmable mechanism of wettability was revealed through the Wenzel model.The bionic surface can be repeatedly used as a “reaction platform” or “tweezer” to achieve the nearly lossless transport of liquid droplets.In addition,friction control can be achieved on the bionic surface.(3)Inspired by the superomniphobic surface with mushroom-like nanoscale re-entrant structures of springtail,a magnetic particle-assisted self-assembly method was developed,and then micropillar arrays with mushroom-like re-entrant structures were fabricated.After chemical modification,a superomniphobic surface with switchable wettability was obtained.The mechanism of wetting switching was elucidated by establishing mathematical models.Actuated by magnetic fields and mechanical strains,surface micropillar morphology and wettability can be reversibly changed to achieve the controllable transportation of oil and water droplets.(4)In order to improve the pressure stability of superomniphobic surfaces,a dual-scale re-entrant structure was designed and prepared using the self-assembly @dip-coating method based on the mushroom-like microscale re-entrant structures.By chemical modification,the fabrication of a superomniphobic surface was achieved.The bionic surface exhibited excellent pressure stability when impacted by high-pressured water droplets and low-surface-tension droplets.The mechanism of dual-scale re-entrant structures to enhance pressure stability was elucidated with mathematical models.The as-prepared surface demonstrated the icing-delay capacity under the condition of rapid depressurization,expanding the application fields of superomniphobic surfaces.(5)Inspired by the slippery surface with wedge-shaped microcavity of Nepenthes,a near-infrared photoresponsive slippery surface with dual-scale re-entrant structures was designed and fabricated.Driven by near-infrared light,the transport of large-volume droplets and the multi-path transport of droplets can be realized due to the photothermal conversion capability of carbonyl iron powder.The driving mechanism of droplets on the slippery surface was revealed through the mechanical analysis. |
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